Are you doing the ice queen method with your condish??? basically you condish your hair upside down and then scrunch and squish it till it feels like seaweed. You wash out the condish with your head upside down. You will also put your product upside down. Then slowly turn your head over and put product in upright. That should definitley help with clumping. If you do a search and type in ice queen you shold be able to find the thread.
Also, not sure if mousse is a strong enough hold product. I could be wrong , though.

Ditto on what Wavy Wonder said about mousse. Mousse creates stringlets on moi. Gel works much better. I do a modified Ice Queen method because I just can't have my head upside down that long. Grace isn't in my vocabulary Play around with gels and see if that works.

I think it's the final combing you're doing that's going to break up your clumps into little stringlets. After combing or brushing, you need to re-clump your hair, and it has to be wet enough to do so.

I do use a Denman brush or a wide-toothed comb when I apply my GVP CO, upside down. Hair is very slick and "seaweedy" at this point. Then I smooth it all together and pile it on top of my head and leave it in until I'm ready to rinse. I rinse but leave plenty of CO still in my hair, usually rinsing upside down. I don't squeeze out all the drips, just a bit, scrunching with my hands.
Then I smooth on and gently rake in or maybe comb/brush in my gel -- but my hair still has to be very wet at this stage so that after combing/raking, it's still wet & slippery enough so that it will clump right back together again when I start scrunching it. If it's too dry, it'll stay stringy and when I scrunch, it'll frizz.
At this stage I scrunch a lot, upside down, sideways, etc. I have to shake my hair around a bit to be sure it's not all sticking to the top of my head or to the nape of my neck. After I've scrunched in enough gel and scrunched out enough water so it's no longer totally dripping wet, I plop.

since i noticed you are new, and the question gets asked a lot, i would suggest hanging out for a few weeks or doing searches before you post just so you don't get people annoyed and when questions get asked a lot they dont get very many responses. sorry if this sounds mean, it's not intended